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Abstract

Overview of Literature: Pain arising at the sacroiliac joint is in most instances dysfunctional without concomitant radiographic findings. There have been some reports in the literature describing the occurrence of sacroiliac joint pain following lumbar spine surgery including laminectomy, discectomy and fusion. However, the issue hasn’t yet been widely evaluated in the literature.

Purpose: The aim of this study is to evaluate the incidence and laterality of dysfunctional sacroillac joint pain following lumbar spine surgery without fixation and to evaluate the efficacy of fluoroscopic or CT guided injection as a diagnostic and therapeutic tool.

Study Design: Forty-four patients suffering back pain and / or lower extremity pain with recent history of spinal operation are included having pain clinically suspicious of being of sacroiliac origin.

Results: 18 patients were males and 26 patients were females. The age of patients ranged from 22 years to 65 years with a mean of 43 years. Previous operation done included 34 patients undergoing single level discectomy, and 10 patients had laminectomy for canal stenosis. Post injection response classified to negative responders (6) and positive responders (38) patients. The duration of improvement in positive responder group lasted from 14 days to 6 months with an average of 73 days.

Conclusion: A painful SIJ should be more considered as a differential diagnosis in patients with low back pain and leg pain in patients with prior lumbar surgery without fixation. The use of accurate diagnostic, therapeutic injections helps both diagnosis and pain relief.

Keywords

Lumbar surgery, Sacroiliac pain, Sacroiliitis, Injections

Introduction

Cases of recurrent low back pain and/or lower extremity pain after
lumbar/lumbosacral surgery are referred to as failed back surgery
syndrome [1]. Several authors have suggested that the sacroiliac
joint (SIJ) may be a possible source of persistent pain [2,3].

The SIJ as a pain generator results in pseudo-radicular symptoms
that may resemble pain generated due to lumbar roots compression.
This diversity of diffuse pain referral may be explained by the fact
that the sacroiliac joint receives liberal innervations from L2 to
S2 roots [4-6]. The SIJ pain referral zones have been reported to
include the posterosuperior iliac spine, lower lumbar region, upper
lumbar region, buttock, greater trochanteric region, groin and
medial thigh, anterior thigh, posterior thigh, lateral thigh, posterior
calf, lateral calf, anterior calf, ankle, and foot [7-9]. Early published
referral patterns of SIJ provocation or irritation were based on
patients’ complaints and physical examination. Dreyfuss et al.
reported that only 4% of patients with SIJ pain marked any pain
above L5 on self-reported pain drawings [10]. Referral of pain into
various locations of the lower extremity does not distinguish SIJ
pain from other pain states. For example, Schwarzer et al. found
that pain below the knee and into the foot was as common in SIJ
pain as for other sources of pain [9]. Slipman et al. conducted a
retrospective study to determine the pain referral patterns in 50
patients with injection-confirmed SIJ pain [11]. The most common
referral patterns for SIJ pain were found to be radiation into the
buttock (94%), lower lumbar region (72%), lower extremity (50%),
groin area (14%), upper lumbar lesion (6%), and abdomen (2%).
Twenty-eight percent of patients experienced pain radiating below
their knee, with (12%) reporting foot pain. Based on the existing
data, the most consistent factor for identifying patients with SIJ
pain is unilateral pain (unless both joints are affected) localized
predominantly below the L5 spinous process.

Pain arising at the sacroiliac joint is in most instances dysfunctional
without concomitant radiographic findings [10]. There have been
some reports in the literature describing the occurrence of sacroiliac
joint pain following lumbar spine surgery including laminectomy,
discectomy and fusion [12-16]. Although the occurrence of this
condition may yield in un-gratifying results as evaluated by the
patient the issue hasn’t yet been widely evaluated in the literature.

The aim of this study is to evaluate dysfunctional sacroiliitis
occurring following lumbar discectomy and/or laminectomy and
evaluate the efficacy of fluoroscopic or CT guided injection as a
diagnostic and therapeutic tool.

Materials and Methods

This study included 44 patients with complaints suggestive of
sacroiliac joint pain post lumbar surgery from a total of 461 patients
undergoing non-instrumented lumbar surgery during through 24
months between February 2014 and February 2016.

All patients had full history taking and complete neurological
examination.

Physical examination tests have been advocated as diagnostic aids
in patients with presumed SIJ pain [17]. Examples of these tests
include Patrick’s test, Yeoman’s test, [18] The Patrick, or FABER
(flexion abduction and external rotation) which stresses the hip
and SIJ. The test is performed by moving the flexed, abducted,
and externally rotated hip to an extended position. If the test is
positive, the patient describes pain at the posterior superior iliac
spine and the SIJ. The Yeoman test is performed with the patient
prone. The test is performed by extending the hip and rotating the
ilium. Usually, the patient will report pain over the posterior SIJ,
specific tenderness over the sacral sulcus as well as the posterior
sacroiliac spine Gaenslen’s test, Gillet’s test, the compression test,
and the thigh thrust test. However, when applying pain provocation
tests, it is nearly impossible to define which structures are actually
stressed [19]. Even structures such as the iliolumbar ligament
or piriformis muscle cannot be excluded as potential sources of
pain because they are functionally related [3,20]. Consequently,
it is very difficult to determine whether the pain that is provoked
is exclusively intra-articular or whether it is related to capsular
ligaments. Previous studies have reported that there is no one
single specific physical examination that can accurately identify a
painful SIJ [5,17,21,22]. Dreyfuss et al. [5,19] found that 20% of
asymptomatic adults had positive findings on commonly performed
SIJ provocation tests and that the test with the highest sensitivity
was the test of sacral sulcus tenderness (89%), although this test
exhibited poor specificity. Slipman et al. [22] reported a positivepredictive
value of 60% in diagnosing SIJ pain in patients using
a positive response to three SIJ provocation tests. Broadhurst
and Bond [23] reported a sensitivity of 77% to 87% for positive
responses to three SIJ provocation tests. Thus, there is evidence
of good diagnostic validity of positive responses to a threshold of
three SIJ provocation tests to identify SIJ pain [23,24]. However,
there are no studies that have specifically examined provocation
tests in patients with SIJ pain after lumbar/lumbosacral fusion.

The outcome of injection was assessed as described by patients in
terms of pain and movement and was classified into two groups:

1. Negative responders (non-sacroiliac joint pain): including those
with no clinical improvement or rapid recurrence of symptoms
within 14 days [7].

2. Positive responders: including those with sustained clinical
improvement further than 14 days (38 patients).

The duration of maximal clinical improvement is recorded.

Results

Forty-four patients meeting the selection criteria were included. 18
patients were males and 26 patients were females. The age of patients
ranged from 22 years to 65 years with a mean of 43 years. The
nature of previous operation done included 34 patients undergoing
single level discectomy (12 patients with microdiscectomy or
fenestration and 22 with formal laminectomy). Ten patients had laminectomy for canal stenosis. Table 1 demonstrates the type of
previous procedure.

Type of intervention

Number of patients (%)

Discectomy

34(77.3%)

Microdiscectomy

12

Discectomy through formal laminectomy

22

Simple laminectomy

10(22.7%)

Table 1: Shows the type of initial intervention.

The occurrence of pain was in the ipsilateral side as preoperative
complaint in 18 patients, and in the contralateral side in 22 patients.
Four patient had no preoperative sciatica but bilateral neurogenic
claudications and developed a new onset of limb pain one in
the right side the other in left side. The distribution of pain was
recorded as shown in Table 2.

Area of pain distribution

Number of patients

Paramedian low back pain

40

Buttock, groin and thigh

38

Leg pain (below knee referral)

26

Ankle and foot

14

Table 2: Shows the distribution of pain among patients.

Examination of patients revealed local tenderness over the sacroiliac
joint in 38 patients, Yeoman test positive in 34 patients, Faber test
positive in 32 patients. The clinical signs are shown in Table 3.

TestÂ

Number of patients
(Total 44)

Number of patient in positive responders (total 38) (%)

SIJ local tenderness

38

34 (89.5%)

Yeoman test

34

30 (79%)

Faber test

32

28 (73.7%)

Table 3: Shows the clinical sign elicited.

X-ray of the sacroiliac joint revealed sclerosis of joint in 6 patients
otherwise it was normal in 38 patients. Fluoroscopy or CT guided
injection was successfully done in all patients with no complications
reported (Figure. 1).

These x-ray findings were detected in older preoperative studies
and were not considered correlating to the new onset of symptoms.

The clinical response of patients was recorded as follows:

* Negative responders: 6

* Positive responders: 38 patients.

Among the positive responder group (38 patients): 16 patients
reported the pain in the same side as preoperative complaint
and 18 patients had pain in the contralateral side to preoperative
complaint and four patient had no preoperative sciatica but was
only complaining neurogenic claudication on exercise. Thirty-four
(89.5%) patients, had positive local tenderness over the joint.

All 38 patients in the positive responder group had more than one
clinical test positive of sacroiliac source of pain.

The incidence of patients proved to have sacroiliac joint generated
pain was 8.2% (38 out of 461).

The duration of improvement in positive responder group lasted
from 14 days to 6 months with an average of 73 days (Figure. 2A and Figure. 2B).

Figure 2: (A) and (B) demonstrates the lateral and axial scans of injecting the left SI joint in a patient with suspected left dysfunctional sacroillitis.

Patients with improvement sustained for 6 month or more: 10
patients.

Patients with improvement sustained for 3-6: 14 patients.

Patients with improvement sustained for 1-3 month: 12 patients.

Patients with improvement sustained for less than 1 month: 2
patients.

Discussion

The sacroiliac joint is a well-known pain generator that may very
much mimic pain generated due to lumbar radiculopathy. This
diversity of diffuse pain referral may be explained by the fact that
the sacroiliac joint receives liberal innervations from L2 to S2
roots [24,25]. The typical symptoms include low back pain that
frequently radiates to the buttocks and thigh or even the leg and
foot [20,26,27].

The clinical examination points to the suspicion of involved
sacroiliac joint as a pain generator, and even though a large number
of provocative clinical tests are described still sure diagnosis
may not be clinically ascertained. These manoeuvres have been
demonstrated to have poor inter- and intratester reliability [28,29], and
have been found positive in 20% of asymptomatic individuals [19].

Radiological investigations including magnetic resonance imaging,
computed tomography, and bone scans of the sacroiliac joint cannot
also reliably determine whether the joint is the source of the pain
and thus controlled analgesic injections of the sacroiliac joint are
the most important tool in the diagnosis [10].

Few reports in the literature have pointed to the occurrence of
sacroiliac joint pain following lumbar spine surgery including
laminectomy, discectomy and fusion [12-16].

The proposed mechanism behind sacroiliac dysfunction following
lumbar procedures particularly spinal fixation include altered
mechanics and new stresses placed over the joint due to correction
of pelvic tilt that accompanies unilateral limb pain [13-15]. In one
study conducted to evaluate sacroiliac joints by SPECT scan it was
found that the uptake of sacroiliac joints increased in patients who
had undergone prior lumbar laminectomy and/or spinal fusion.
Such spinal surgery can increase impact loading on the SIJ, leading
to mechanical overload and functional sacroiliitis [14].

Although the sure diagnosis of this condition requires diagnostic
injection, the presence of sacroiliac tenderness is one of the most
consistent findings in patients with sacroiliac dysfunction. The
positivity of multiple provocative tests raises more confidence in
the diagnosis [18]. Sacroiliac joint local tenderness was present in
38 (86.4%) patients in the positive responder group in this series.
All negative responders (6 patients) had a single clinical positive
test suspecting sacroiliac joint pain.

In this study we have selected patients with high clinical
suspicion of having sacroiliitis as a pain generator following
initial improvement after lumbar spine surgery. We have selected
to perform a diagnostic/ therapeutic injection but using the
fluoroscopic or CT guidance technique. Several techniques for
injection has been described. The free hand technique has a very
high incidence of improper placement of needle in about 50% of
cases [25,30] and thus bedside injection may be very misleading
in result. Fluoroscopy guided injections are also accurate but may
require the injection of dye into the joint and utilizes large dose
of radiation. The use of CT for needle placement is unmatched in accuracy besides the easy localization in obese patients and
selection of the target whether intra-articular or periarticular [31].

Our results have shown that the sacroiliac joint was the pain
generator in 38 patients (86.4%) of those clinically suspected
of having the condition and only 6 patients (13.6%) were nonresponders,
whereas most surgeons are familiar with causes of
failed back including scarring, adhesions, recurrence of disc and
facet arthropathy, painful sacroiliac joint may not be as familiar and
therefore may not be considered in patients with back or leg pain
after spinal operations [13].

The selection criteria of patients in this study, included absence
of spinal pathology that might be responsible for the patient’s
complaint. In clinical practice, however, concomitant asymptomatic
radiological findings including a lumbar disc herniation may
coincidently be present but not responsible for the patient’s
complaint. Irwin and Haris [25], reported two cases of lumbar disc
herniation who failed to improve after transforaminal steroid root
injection. Both patients proved to be of dysfunctional sacroiliac
joint nature later on. Thus, patients with clinical suspicion of having
sacroiliac joint pain even in presence of MRI findings that might
cause the radiculopathy should undergo a diagnostic injection
before unnecessary discectomy is performed.

The numbers of patients in who prolonged improvement among
positive responders in our study were 24 patients (63.2%) whereas
14 patients (36.8%) were documented as sacroiliac joint pain
but with shorter duration of clinical improvement. Patients with
documented diagnosis can further be managed by repeated injection
and in resistant cases, radiofrequency ablation or sacroiliac
arthrodesis may be considered [1,32].

The overall incidence of post non-instrumented SIJ pain was
found to be 8.2% which is lower than the reported incidence of
SIJ pain in instrumented posterior lumbar fixation. The new onset
lower extremity symptoms among positive responder patient group
occurred in the ipsilateral side of previous complaint in 42.1% of
cases and in contralateral side in 47.4% denoting that the stress
loads may affect either side.

Conclusion

The use of diagnostic injections should increase by the spine
surgeons. A painful SIJ should be more considered as a differential
diagnosis in patients with low back pain and leg pain in patients
with prior lumbar. The use of accurate diagnostic, therapeutic
injections helps both diagnosis and pain relief.